Concepts Of Physics MCQ Edition [Volume 1]PhysicsSome Mechanical Properties of Matter
When we speak of the surface of a liquid, we are referring to
Options
- Aa layer with a thickness on the order of 10⁻⁸ m
- Ball the molecules exposed to the atmosphere
- Ca layer with a thickness on the order of 10⁻⁴ m
- Da geometrical plane such as x = 0
Correct answer
A. a layer with a thickness on the order of 10⁻⁸ m
Step-by-step solution
The surface of a liquid is not a mere geometrical plane but a layer of finite thickness known as the surface film. The thickness of this layer is equal to the molecular range, which is the maximum distance up to which the intermolecular forces of attraction are effective. The molecular range for liquids is of the order of 10⁻⁹ m to 10⁻⁸ m . Therefore, the surface of a liquid refers to a layer with a thickness on the order of 10⁻⁸ m .